Matrix element reweighting is a powerful experimental technique
widely employed to maximize the amount of information that can
be extracted from a collider data set. Given a set of theoretical
hypotheses and a sample of experimental events, the method assigns
a weight to each hypothesis on an event-by-event basis and in
this way provides a discriminator between different theoretical
assumptions. The computation of the weights is intricate, because
it involves a difficult convolution of the theoretical information
on the hard scattering with the experimentally available information
on the final state. In this talk, I will present a general algorithm
aimed at evaluating the weights appearing in the matrix element
method for any process of interest in the standard model and beyond.
The implementation builds on MadGraph, and is completely automated.
I will also discuss a few sample applications that show the capabilities
of the code and illustrate the possibilities for new studies that
such an approach opens up. (The talk is based on work presented
arxiv:1007.3300.)
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